McGill is a census-designated place in White Pine County, Nevada, United States. The population was 1,148 at the 2010 census. In 1872, John Cowger established a ranch in the Steptoe Valley and acquired the water rights for the area. William Lyons and William McGill purchased the ranch in 1886. A post office was established at the ranch, now named McGi…McGill is a census-designated place in White Pine County, Nevada, United States. The population was 1,148 at the 2010 census. In 1872, John Cowger established a ranch in the Steptoe Valley and acquired the water rights for the area. William Lyons and William McGill purchased the ranch in 1886. A post office was established at the ranch, now named McGill Ranch, in 1891.